KR20020055999A - Method for Fabricating of Liquid Crystal Display - Google Patents

Abstract

PURPOSE: A method of fabricating a liquid crystal display is provided to prevent electrical interference of a pixel electrode according to a semiconductor material by employing an exposure process using negative photoresist. CONSTITUTION: A gate insulating layer(27) is formed on a transparent substrate(21). A semiconductor layer(29) is formed on the gate insulating layer. Negative photoresist(26) is coated on the semiconductor layer and selectively exposed using a predetermined mask pattern(24). The transparent substrate on which the negative photoresist is coated is heat-treated. Negative photoresist including impurities is removed using a developer and, simultaneously, the exposed negative photoresist is developed to form a photoresist pattern. The semiconductor layer is patterned using the photoresist pattern.

Description

Method for manufacturing a liquid crystal display {Method for Fabricating of Liquid Crystal Display}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a method for manufacturing the same, and more particularly to a method for manufacturing a liquid crystal display device for preventing a defect of a pixel electrode caused by a semiconductor material.

In general, a liquid crystal display (LCD) displays an image by adjusting light transmittance of liquid crystal cells according to a video signal. Among the liquid crystal display devices, an active matrix type in which switching elements are provided for each liquid crystal cell is suitable for displaying a moving image. In the active matrix liquid crystal display device, a thin film transistor (hereinafter referred to as TFT) is mainly used as a switching element.

1 is a plan view illustrating a conventional liquid crystal display device.

Referring to FIG. 1, the liquid crystal display according to the related art is electrically connected to the active layer 9 through the gate electrode 5, the gate insulating layer 7, the active layer 9, and the contact hole 10 formed on the substrate 1. Thin Film Transistors (hereinafter referred to as TFTs) including source and drain electrodes 15 and 17 formed to be connected to each other are provided.

The TFT supplies the data signal on the data line 13 to the pixel electrode 18 during the scan pulse period applied to the gate electrode 5. The gate electrode 5 is connected to the gate line 3, and the source electrode 15 is connected to the data line 13. The drain electrode 17 has an indium tin oxide (hereinafter referred to as "ITO") and an indium zinc oxide (hereinafter referred to as "ITO") as a conductive material through the contact hole 10. IZO ") and indium-tin-zinc-oxide (hereinafter referred to as " ITZO "). A gate insulating film 7 formed of an inorganic insulating material is formed on the source electrode 15 and the data line 13, and an active layer 9 is deposited thereon. On this TFT, a protective layer 16 made of an inorganic insulating material or an organic insulating material is formed.

2A to 2F are cutaway views illustrating a method of manufacturing the liquid crystal display device shown in FIG. 1 along a line "A, A '". In particular, only the thin film transistor unit and the data line unit are illustrated.

Referring to FIG. 2A, aluminum (Al), copper (Cu), or the like is deposited on the transparent substrate 1 by a method such as sputtering to form a metal thin film. The metal thin film is patterned by a photolithography method including a wet method to form a gate electrode 5 on the transparent substrate 1. The gate insulating film 7 is formed on the transparent substrate 1 so as to cover the gate electrode 5. The gate insulating film 7 is formed by depositing an insulating material with silicon nitride or silicon oxide.

2B and 2C, the active layer 9 and the ohmic contact layer 11 are sequentially formed in the TFT and data line 13 regions by chemical vapor deposition (hereinafter referred to as “CVD”). . The active layer 9 is formed of amorphous silicon or polycrystalline silicon that is not doped with impurities. In addition, the ohmic contact layer 11 is formed of amorphous silicon or polycrystalline silicon doped with N-type or P-type impurities.

The ohmic contact layer 11 and the active layer 9 of the TFT are patterned so that the gate insulating film 7 is exposed by a photolithography method including this method angle so that only the portion corresponding to the gate electrode 5 remains. At this time, the active layer 9 and the ohmic contact layer 11 are allowed to remain only in the portion corresponding to the gate electrode 5.

A positive photoresist 6 is coated on the active layer 12 and the ohmic contact layer 14 in the data line 13 region. The positive photoresist 6 is usually coated by spin coating in order to obtain a flat and uniform thickness. The active layer 12 and the ohmic contact layer 14 in the region of the data line 13 are exposed to ultraviolet rays in a region other than the region corresponding to the chromium pattern by the positive photomask 4 having the chromium pattern. The active layer 12 and the ohmic contact layer 14 in the region exposed to ultraviolet rays are removed by an etching process. Since the photoresist 6 in the region corresponding to the chromium pattern is not exposed to ultraviolet rays, the photoresist 6 does not undergo a photochemical reaction, and thus the active layer 12 and the ohmic contact layer 14 corresponding to the chromium pattern remain.

Referring to FIG. 2D, a molybdenum alloy such as molybdenum (Mo), MoW, MoTa, or MoNb is covered by the CVD method or the sputtering method on the gate insulating film 7 to cover the ohmic contact layer 11. Deposit. The deposited metal or metal alloy is in ohmic contact with the ohmic contact layer 11.

The metal or metal alloy is patterned by a photolithography method so that the gate insulating film 7 is exposed to form data lines 13 perpendicular to the gate lines 3 and source and drain electrodes 15 and 17.

In the above, the ohmic contact layer 11 of the portion corresponding to the gate electrode 5 between the source and drain electrodes 15 and 17 is also patterned to expose the active layer 9. The portion corresponding to the gate electrode between the source and drain electrodes 15 and 17 of the active layer 9 becomes a channel.

Referring to FIG. 2E, an inorganic insulating material such as silicon nitride or silicon oxide or an acrylic organic compound such as silicon nitride or silicon oxide, Teflon, BCB so as to cover the source and drain electrodes 15 and 17 on the gate insulating layer 7 is illustrated. A protective layer 16 is formed by depositing an organic insulator having a low dielectric constant such as (benzocyclobutene), cytotope, or perfluorocyclobutane (PFCB).

Referring to FIG. 2F, a transparent conductive material such as ITO, IZO, or ITZO is deposited on the protective layer 16 through the contact hole 10 to form the pixel electrode 18. The pixel electrode 18 is in electrical contact with the drain electrode 17 through the contact hole 10.

However, as shown in FIGS. 2B and 2C, when the active layer and the ohmic contact layer are exposed by forming the active layer and the ohmic contact layer on the data line, the foreign material does not expose the active layer and the ohmic contact layer by the foreign matter. Will grow. Accordingly, the active layer and the ohmic contact layer are formed larger than the data lines, thereby causing electrical influence on the pixel electrode of the TFT element, thereby causing electrical interference, and causing defects in the process pattern.

Accordingly, an object of the present invention is to provide a method of manufacturing a liquid crystal display device for preventing defects in the electrical interference of a pixel electrode by a semiconductor material by performing an exposure process using a chemically amplified negative photomask.

1 is a plan view showing a conventional liquid crystal display device.

2A through 2F are cross-sectional views illustrating a method of manufacturing the liquid crystal display shown in FIG. 1, taken along a line "A, A '".

3 is a plan view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

4A to 4F are cross-sectional views illustrating a method of manufacturing the liquid crystal display shown in FIG. 3, taken along the lines " B, B '"

<Brief description of symbols for the main parts of the drawings>

1,21: transparent substrate 3,23: gate line

5,25, gate electrode 7,27 gate insulating film

9,12,29,32: Active layer 10,30: Contact hole

11,14,34,31: Ohmic contact layer 13,20,33,40: Data line

15,35 source electrode 16,36 protective layer

17,37: drain electrode 18,38: pixel electrode

4: positive photomask 24: negative photomask

6: positive photoresist 26: negative photoresist

According to another aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, the method including: forming a gate insulating film on a transparent substrate and forming a gate insulating film on the transparent substrate; Forming an entire surface of the semiconductor layer, forming an entire surface of a negative photoresist on the semiconductor layer, aligning a mask pattern on the negative photoresist, and exposing the negative photoresist through the mask pattern. And heat treating the exposed negative photoresist to a predetermined temperature, removing the negative photoresist containing foreign matter with a developer, and simultaneously developing the exposed negative photoresist to form a photoresist pattern; The semiconductor using a resist pattern A characterized in that it comprises the step of patterning.

Other objects and features of the present invention in addition to the above object will become apparent from the description of the accompanying examples.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 3 to 4F.

Referring to FIG. 3, in the liquid crystal display according to the present invention, the active layer 29 is formed through the gate electrode 25, the gate insulating layer 27, the active layer 29, and the contact hole 30 formed on the substrate 21. And a thin film transistor (hereinafter referred to as "TFT") including source and drain electrodes 35 and 37 formed to be electrically connected to each other.

The TFT supplies the data signal on the data line 33 to the pixel electrode 38 during the scan pulse period applied to the gate electrode 25. The gate electrode 25 is connected to the gate line 23, and the source electrode 35 is connected to the data line 33. The drain electrode 37 has an indium tin oxide (hereinafter referred to as "ITO") and an indium zinc oxide (hereinafter referred to as "ITO") as a conductive material through the contact hole 30. IZO ") and indium-tin-zinc-oxide (hereinafter referred to as " ITZO &quot;). A gate insulating layer 27 formed of an inorganic insulating material is formed on the source electrode 35 and the data line 33, and an active layer 29 is deposited thereon. On this TFT, a protective layer 36 made of an inorganic insulating material or an organic insulating material is formed.

4A to 4F are cutaway views illustrating a method of manufacturing the liquid crystal display shown in FIG. 3 along the lines " B, B '", specifically showing only the thin film transistor portion and the data line portion.

Referring to FIG. 4A, a metal thin film is formed by depositing aluminum (Al), copper (Cu), or the like on the transparent substrate 21 by sputtering or the like. The metal thin film is patterned by a photolithography method including a wet method to form the gate electrode 25 on the transparent substrate 21. The gate insulating film 27 is formed on the transparent substrate 21 to cover the gate electrode 25. The gate insulating film 27 is formed by depositing an insulating material with silicon nitride or silicon oxide.

4B and 4C, the active layer 29 and the ohmic contact layer 31 are sequentially formed in the TFT and data line 33 regions by chemical vapor deposition (hereinafter referred to as “CVD”). . The active layer 29 is formed of amorphous silicon or polycrystalline silicon that is not doped with impurities. In addition, the ohmic contact layer 31 is formed of amorphous silicon or polycrystalline silicon doped with N-type or P-type impurities at a high concentration.

The ohmic contact layer 31 and the active layer 29 of the TFT are patterned so that the gate insulating film 27 is exposed by a photolithography method including this method angle so that only the portion corresponding to the gate electrode 25 remains. At this time, the active layer 29 and the ohmic contact layer 31 are allowed to remain only in the portion corresponding to the gate electrode 25.

When foreign matter is formed on the active layer 29 and the ohmic contact layer 31 in the data line 33 region, a negative photoresist 26 is coated on the active layer and the ohmic contact layer including the foreign matter. The negative photoresist 26 is usually coated by spin coating in order to obtain a flat and uniform thickness. The negative photoresist 26 is composed of a PAG (Poto Acid Generator; hereinafter referred to as "PAG"), a resin, a cross-linker, and a small amount of additives. The active layer 29 and the ohmic contact layer 31 of the data line 33 region are blocked by ultraviolet rays in a region corresponding to the chromium pattern by a negative photo mask of a chromium pattern, and the photoresist of the region outside the chromium pattern is exposed to ultraviolet rays. Exposed. Photoresists containing foreign substances exposed to ultraviolet rays are exposed to ultraviolet rays, but they do not receive sufficient energy due to poor focus and increased thickness of the photoresist. H +) does not occur. Therefore, the cross-linker does not crosslink in the photoresist even when the substrate is heated to a temperature between 100 and 150 degrees in the PEB process, so that the photoresist containing the foreign matter is 2.38% tetramethyl ammonium hydro It is dissolved in the developer of Tetra Methly Ammonium Hydro-Oxide (TMAH) and removed, so it does not cause pattern defects caused by foreign substances when using positive photoresist, and causes short circuit. In addition, the effect is applied to the same effect even if there is a foreign material in the periphery forming the semiconductor layer pattern appears.

In addition, the top portion where no foreign matter exists forms an acid by the PAG component,

PEB (Post Exposure Baking) process. In other words, when heat is applied between 100 and 150 degrees, the cross-link component is combined with acid to change the molecular structure which is not dissolved in 2.38% TMAH. In the unirradiated area, it is dissolved and removed by a developer of 2.38% TMAH, and in the irradiated area, UV is not dissolved and forms a pattern.

Referring to FIG. 4D, a molybdenum alloy such as molybdenum (Mo), MoW, MoTa, or MoNb is covered on the gate insulating layer 27 by a CVD method or a sputtering method to cover the ohmic contact layer 31. Deposit. The metal or metal alloy deposited above is in ohmic contact with the ohmic contact layer 31.

The metal or metal alloy is patterned by a photolithography method so that the gate insulating layer 27 is exposed to form data lines 33 and source and drain electrodes 35 and 37 perpendicular to the gate lines 23.

The ohmic contact layer 31 of the portion corresponding to the gate electrode 25 between the source and drain electrodes 35 and 37 is also patterned to expose the active layer 29. The portion corresponding to the gate electrode between the source and drain electrodes 35 and 37 of the active layer 29 becomes a channel.

Referring to FIG. 4E, an inorganic insulating material such as silicon nitride or silicon oxide or an acrylic organic compound such as silicon nitride or silicon oxide, Teflon, BCB is formed to cover the source and drain electrodes 35 and 37 on the gate insulating layer 27. A protective layer 36 is formed by depositing an organic insulator having a low dielectric constant such as (benzocyclobutene), cytotope, or perfluorocyclobutane (PFCB).

Referring to FIG. 4F, a transparent conductive material such as ITO, IZO, or ITZO is deposited on the protective layer 36 through the contact hole 30 to form the pixel electrode 38. The pixel electrode 38 is in electrical contact with the drain electrode 37 through the contact hole 30.

In this process, the liquid crystal display according to the present invention etches the semiconductor layer on which the foreign matter is formed by using a negative photomask to disconnect the semiconductor layer. However, the disconnected semiconductor layer does not affect the electrical signal and thus does not cause defects in the process, and may eliminate electrical interference with the pixel electrode.

As described above, the manufacturing method of the liquid crystal display device according to the present invention can prevent the process defect due to the interference between the pixel electrode and the channel layer by preventing the pattern defect caused by the foreign matter generated in the exposure process, the yield is improved Can be. In addition, unnecessary rework rate can be reduced.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (8)

Forming an entire gate insulating film on the transparent substrate; Forming an entire semiconductor layer on the gate insulating film; Exposing a negative photoresist on the semiconductor layer to expose the negative photoresist using a mask pattern; Heat-treating the transparent substrate on which the negative photoresist is formed; Removing the negative photoresist containing foreign matter with a developer and simultaneously developing the exposed negative photoresist to form a photoresist pattern; And patterning the semiconductor layer using the photoresist pattern. The method of claim 1, The heat treatment of the exposed negative photoresist is heated to a temperature of 100 to 150 degrees. The method of claim 1, The developer is a manufacturing method of a liquid crystal display device using a developer of 2.38% Tetra Methly Ammonium Hydro-Oxide (TMAH). The method of claim 1, And a gate line is formed between the transparent substrate and the gate insulating layer. The method of claim 1, And forming a data line entirely on the semiconductor layer. The method of claim 5, And forming an entire protective layer on the data line. The method of claim 6, And forming a contact hole on the passivation layer to expose the data line. The method of claim 7, wherein And forming a pixel electrode on the passivation layer so as to contact the data line via the contact hole.